I had uw-imap running fine, but I wanted to switch to courier-imap and maildir format.
Now, everything seems configured properly and works, but I can only receive mail from the server, so only local mail. If I try to send a message from another account using my ISP I don't receive the mail. Sending works flawlessly. I just can't get any email from outside.

Tested exim.conf and it works, I didn't change my .fetchmailrc, so I have no idea what the solution is.
Can someone help me?

That sounds like a SMTP server problem, not a imap server problem.

How so? I can send email perfectly from the imap account but not receive any email to the imap account unless it comes from a local user.
Besides, the smtp server is the one from my ISP, the imap server is on the LAN here.

I must have miss understood what you ment then.

I read " but I can only receive mail from the server, so only local mail. If I try to send a message from another account using my ISP I don't receive the mail. Sending works flawlessly. I just can't get any email from outside." I thought you ment that mail sent to your machine from a local user you could get through the IMAP server and mail send from another account to your machine you couldn't get through the IMAP server.

Tell me more about your mail server setup. What MTA you are using (sendmail, postfix, qmail) ect.

I had uw-imap working. But switched to courier-imap.
I'm running a Debian server with exim and fetchmail configured. I want to be able to recieve my ISP mail on my server here at home and read it via imap, so I can access my email from anywhere I want.
If I test my exim.conf on the server with for example:
I receive that email (checked it with Mozilla Mail).
But when I want to send an email with for example Mozilla mail from another account or any other mail client from another machine, I don't receive the email.

Oh, I'm using qpopper for pop3 server and I'm running it on a Debian server.

Could there be something wrong with qpopper?

Possibly, how is the mail stored on disk? Is it put into an mbox file or is it put into maildirs? and if it is mail dirs are the file name make-ups different if the mail is pulled from your ISP or created with "mail -s "Test message" username".

I have found that if I pull mail from one server and put it in my directory on another (with maildir) courier only displays the mail that was delivered specifically to my machine. Because the domain of the machine is in the file name for the message.

Well, that's the problem, I think my mail doesn't get to my machine.
Bear with me, I'm a newbie at this, but I think it should work like this:
Fetchmail gets the mail from my ISP, using qpopper with imap I can retrieve the mail from the server. Is that it?
But apparently the server isn't able to get the mail from my ISP. Weird. I'm getting tired of this.